2 Place Collimated Display

[geneb]

I started working on the new collimated display design yesterday after our resident Mathgician worked his magic. (*waves at Wayne*) :D

This first new project will fit cockpits that are Cessna 182 sized. It should also work out for small bizjets like _maybe_ the Lear 45 or some of the smaller Embraers.

That being said, this thing is NOT small. The 180 degree screen design is 86.444 inches wide (that's about 7ft 1/4in). The mirror will have a radius of 72 inches and will take up more space than that as the sphere radius is defined inside the framework. Once I get the rest of the components completed, I'll be able to tell you how much ceiling height you'll need. :)

Here's two renders of what the screen components look like. There are three primary components to the screen - an upper frame, a lower frame and and upper frame spreader bar. The shape is defined by 30 "blades" that will fit into the upper and lower frames. This build will go just like the last one did with respect to the screen.

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I don't know yet how much this will cost. I do know that we'll offer both CAD drawings on CD as well as a "short" kit that will consist ONLY of parts that really should be CNC cut. You'll be on your own for the rest of the materials, fasteners and Mylar - we'll point you to our vendor so you can buy the film directly from them. The part kits will be shipped in crates made from 2x4s and 1/4" OSB. The material used will be 18mm and 12mm (essentially 3/4" and 1/2") Russian Birch.

If you don't want to worry about shipping & crating charges, the CD will include all the necessary files to hand off to a local fabber - they can be found at http://www.100kgarages.com.

Wayne tells me the 737 mirror will be a bit over 15ft in diameter, so if you guys with the big jet habit REALLY want a collimated display, you'd better hope you've got room for it. :) I would recommend consulting a good engineer before you start cutting rafters though. *laughs*

I'll update this thread as progress happens.

g.

[Mike.Powell]

Sweet! Anything worth doing is worth doing to excess!;)

Looking forward to it, Gene.

[fsaviator]

Wayne tells me the 737 mirror will be a bit over 15ft in diameter, so if you guys with the big jet habit REALLY want a collimated display, you'd better hope you've got room for it. :) I would recommend consulting a good engineer before you start cutting rafters though. *laughs*
g.

So what you're telling me, Gene, is that as soon as I get to Germany next month, I should be shopping for a house with a room at least 15' wide? Check!

[Efe Cem Elci]

Sign me up for the CD Gene...

[Tom_G_2010]

Ditto!!!! CD for sure. And, depending on the price point the pre-fab may be of interest.

I believe I've got the space for the radius mentioned, but the height may be an issue so I'll be watching closely to see what that turns out to be. I guess I could always try to snag some warehouse space from the family business...

[geneb]

Thanks all!

The 15' diameter is for the mirror sphere _only_. The framework will add 24" or so (at least) to each side.

One of the design changes I'm making for the new mirror chassis will be a better looking back to the assembly. The back will be made of a pair of 1/8" hardboard panels that are laminated into a conic shape on a jig.
This design change will do a few things:

1. It will remove the need for a special grid support structure to prevent the back from deforming under vacuum.
2. It will greatly reduce the interior air volume of the mirror. The airspace on commercial displays is very small - typically there is very little space between the back surface of the mirror and the front surface of the vacuum plenum.
3. It will reduce the width of the mirror chassis, but not by much. :)

The conic back sections will be probably the trickiest parts of the whole project to build. The two parts that make up the lamination will be different sizes to account for the k-factor when you bend them in order to make the edges line up correctly. Forming the sections will require a two part jig. The bottom will be a "positive" shape and the top will be a "negative" shape. The 2 1/8" hardboard sheets will be clamped between these jigs in order to form the sheets into a conic section that will retain it's shape when the glue dries. You'll be able to make the jig out of 7/16" OSB which is a pretty cheap material. You're only going to use it three times, so it doesn't make sense to use expensive plywood for it.

g.

[castle]

Hi Gene,

Is that 24 inches x 2 = 4 feet added to the 15 foot diameter". Seems like that would create a rather large volume? Also what is the diameter of the mirror at the bottom? 15' x cos( 50 degrees ) = 9.64' ? Ceiling height is 12' don't think that will be a problem and length of the space is 24'; however depth (width) of the stall is about 12.5 feet. That might be a little tight, but doable.

Regards
Jack

[geneb]

Jack, remember that the diameter of the mirror is as measured at the film itself. That doesn't include any structure to support it. My 24" addition to each side was simply a guess based on what I've got now. Also, the mirror is only 40 degrees high (0 at the top, down to 40), not 50.

--edit--
After thinking about it a little bit more, the "extension" past the mirror diameter will more than likely be under 8". I simply got my top & bottom dimensions flipped around.
-------
I've been catching up on house maintenance tasks this week, so no new work has been done. (I'm about six months behind THAT too. *sigh*)

g.

[castle]

Having just moved I know the feeling, the "honey-do" list keeps growing while a lot of the sim parts are still in boxes :-(

Trying to visualize ( mirror/cockpit positioning ) the layout and tend to think in terms of two numbers; the screen diameter at the equator and at the southern edge of the FOV. Structure behind the mirror at the equator sets the total system size and the bottom number plus structure forward determines how much cockpit structure clearance exists when unit is positioned for the correct eyepoint(s).

Is the 15' mirror size based on the footprint of many of the shell plans available for the 737?
Might it be possible to use a smaller mirror? Reduce amount of materials required as well as the space. Or are we at the minimum acceptable limit?

Jack

[geneb]

As far as I know, the 15' (approximate!) diameter is based on a real 737 flight deck section.

The size of the mirror is dictated primarily by the size of the simulator cab.

g.

[castle]

Most of the 737 sim shells truncate the nose section at the apex of the windscreen plus about a foot for one additonal rib for structual stiffness. From pilot's eyepoint to the front is around 6 to 7 feet.

The width at the forward windscreen (corner to corner) is 5.5 feet at the base and 7.5 feet at the rear of the side windows. allowing for a little bit of fuselage bulge below the windows might add about a foot. So the shell exterior is around 9 feet, maybe a little more or less. So the lower boundary is 15Xcos(40) = 11.5 feet. and you need some room, so maybe a 15' diameter mirror is right-sized.

Looking forward to the final set of plans you provide.

Jack

[JTRACKER]

Gene, I didn't see any mention of the release date of the CD.

It would be nice to get this job scheduled in before more gardening chores get me too exhausted to play ;)

Definitely put me down for one if those CD's as well.

Glad to see you're back in action !

[geneb]

I didn't mention a date because there isn't one. :)

It will get done when it gets done - I'm not going to do a rush job just to get it out the door.

Last week I junked the screen design because I had a few errors in it and I didn't like the overall structure. It's been redesigned at 210 degrees and is a bit more stout.

g.

[castle]

[QUOTE=geneb;131038]I started working on the new collimated display design yesterday after our resident Mathgician worked his magic. (*waves at Wayne*) :D

Hi Gene,

when you have a sec how about a short progress report on the larger mirror system. And the smaller unit for that matter.

Thanks
Jack

[geneb]

Sure!

The larger unit doesn't exist yet. :) The current design is for the Cessna 182 "sized" display.

As of Friday, the mirror cell design is completed with the exception of the "ears". (I'll get into that in a moment) I've also started on the support structure for the screen. I suspect I'll have this mostly completed by Wednesday night barring any interruptions.

The plan is to get this model completed and then begin design work on the 737ish sized model, followed by the "tiny" model that is the same size of the unit that Wayne & I built. The 737ish and tiny model designs should go a LOT faster as I will have solved all the integration issues with this first design.

After the tiny design is done, I'm going to build that and use it to write the assembly guide for the other two display designs. One manual will cover all three because while the size & geometry will be different for each of the three, the displays will all use the same shape & number of components.

After the new tiny model is built, I'll start looking for a guinea pig to build the Cessna 182 sized display. Jack, you're already my test victim for the 737ish unit. :)

When the test builders are done and happy with the results, I'll begin selling drawings and router templates.

I will warn you right now - if you don't own or have ready access to a good router, a full sized band saw and (likely) a table saw, you will NOT be able to build this display. If (and only if) demand is great enough, I may offer a "short" kit that would contain all the mirror cell ribs, screen shape ribs and other parts. I will be including the items necessary for a builder to have the parts CNC cut with as little hassle as possible. (Pre-nested parts layout on a 4x8 sheet, etc. I'll also include Vectric VCarve Pro and Aspire design files so you can just hand those off to a fabber and they can run them will little hassle.)

Also note that for the Cessna 182 and 737ish designs, the foam used for the screens will likely exceed the material costs for the rest of the display. The screens are *HUGE* and will eat up a ton of foam to create the shape. This is one of the reasons I'm using test-builders - I simply can't afford the material cost to build something I'll never use. (They're just too big and I'm getting space-constrained in the shop as it is).

Now, as to the "ears"...

Here's the deal - I'm not going to provide design drawings for the end extensions for the display. After thinking about it a great deal and watching Apple go batsh*t crazy and sue Samsung over a rectangle with rounded corners, I'm not up for exposing myself to a suit if Rockwell-Collins decides I need to be made an example of.

That being said, what I will do is provide the builder with enough clues so they can figure it out. I'll post a ton of pictures of how I did it as well as point out the patent so folks can understand the science behind it. Hopefully the "beta" builders would be willing to share their experiences with it as well.

g.

[JTRACKER]

Hi G,

I'm sure looking forward to completion and finally being on your customer list :cool:

JT

[Robjw]

Any updates on the CD? Put me down for one.

[OmniAtlas]

Would this work for a FDS Jetmax style cockpit?

[castle]

Starting down the road to insanity!

First a world of thanks and shout-outs to Gene and Wayne for their time and dedication in completing the design and review of the 737 mirror system. Their efforts and talents represent everything that is right with the world and serve as an inspiration to all hobbyists and DIY simmers.

The drawings and cut files have been sent to the CNC woodshop that will produce the various pieces for assembling the mirror system and will be delivered in two weeks. Then the fun begins in putting it all together....

A couple of preliminary thoughts and observations...

You ABSOLUTELY need a CNC router. The structure uses over thirty 4x8 foot sheets of plywood and hardboard of varying thickness from 3/4" to 1/8". Initially, I considered using a hand router but the amount of cutting and precision required quickly squelched that approach. Either you have a CNC router or access to one.

As to space and size, it is a large structure. The room where I'll house the sim is 16x22x11 feet. You might be able to get by with less floor space but you need the height (perhaps a min of 10 feet ) to hold the projection screen and if your sim sits on a platform above the ground floor you need to account for that as well.

Some of the parts you will have to build yourself, so some woodworking tools and a modicum of skills are required.

And, again, remember how the optics work. The mirror creates a virtual image focused at infinity, not an image projected onto a cylindrical or spherical surface. With a simple projection sysem you can "get away" with some imperfections, inaccuracies, and misalignment of the surface; with the collimated display that is not the case. Misalign, twist, malform the mirror and it will not work. accuracy and precision is the watchword!

Hopefully, will find the time to post updates, pics, and videos of the progress. as well as notes and tips on construction and assembly.

Cheers
JW

[fsaviator]

Outstanding news, John. Looking forward to watching this come together. Keep us posted!

Warren

[castle]

Will do and when you return from your tour in Germany we'll have to think about building another one for your setup.

JW


Outstanding news, John. Looking forward to watching this come together. Keep us posted!

Warren

[fsaviator]

That would be great! Looking forward to already.

Warren

[castle]

It took about two weeks to produce all the pieces for Gene's design. In all it took all of thirty 4x8 sheets of varying thickness from 3/4" plywood to 1/8" hardboard. Started pulling it all together this Friday.

To produce the twelve collar sections for the mirror frame required laminating thirty six pieces into 30 degree arc sections
( three pieces per section ). Required a special bandsaw setup to cut the 20 degree bevel required to hold the collar mask and clamp. The pieces are just too large and heavy to try and work without a jig to hold the cut on line. One comment to Gene, we might want to rethink how these parts are produced for the larger design.

75907589
Not totally convinced this will work especially for the much larger upper sections. But have some ideas if this proves too difficult without a more industrial sort of setup. Waiting for some new bandsaw blades before proceeding. In the mean time moving on to start on the wing ends. Once you see the pics it will be fairly obvious how to produce this section. Think about building a dish of a certain radius and then cutting it in half.

We said this was a large beastie, but studying the CAD files alone does not fully impress upon the reader the size until you see it up close and personal. Here are a few more pics of the wings. (Hint) Can you draw a circle?

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Cheers
JW

[OmniAtlas]

Wow, please keep us updated!

[Robjw]

What would be the space requirements for a GA collimated display for a 182 size cockpit?

[castle]

Time for a short progress report. The two end sections for the mirror frame are completed.764376447645
Will add a two more cross-stringers to beef up the back and prevent "oil-canning". going to hold off adding the front semi-circular cover until mating with the adjoining 60 degree section.

here is a pic of the projection screen frame and ribs.
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To save weight the collar was cut from 1/2" ply. Then the puzzle joints were doubled with 3/4" ply to increase strength and rigidity. Won't get around to actually building the projection screen until the sim room is ready around mid-May, weather permitting we should start construction in a couple of weeks.

Cutting the frame collars for the 20 degree bevel was very successful. You can go to youtube, search on "737castle" and view the short video. Will be posting additional videos on project progress as time goes by. The not so good news is that using the lower grade of plywood resulted in some warping on the sections that could not be corrected. Decision was made to recut the mirror pieces with a better grade of birch plywood that was very close to cabinet grade. These were delivered today and will start fabrication of the 60 degree sections later this week.

Hmm, seems more like a wood working project ;-)

Cheers
JW

[castle]

recutting the mirror frame pieces was a lesson learned -- better to spend a little time and expense to do it right the first time. The mirror is critical and any warping or misalignment will ruin the collimation.
7648 7649 7650

the lower curved pieces in the second pic are the guides for constructing the table on the bandsaw to help align the collar sections as they pass through the saw for the 20 degree bevel cut.

Next I'll post some pics of the support table. Here it is also important to make certain the structure is level to avoid bending of the mirror frame and strong enough to support the weight.

Cheers

[geneb]

Looks great!

g.

[javcr]

Hi all, i have already my Sim working whit fresnel, it looks good but collimated dsplays are almost a dream , i am trying to get some Information about the optics, now looking this excelent work the collimated displays looks not impossible, how i can contact to geneb for Information And cost ? Thanks for sharing this work
javcr@cever.com.mx

[castle]

This will be my last progress report for a few months. starting construction on the new workshop(man-cave) next week. Once that is done, hopefully in late August will reassemble the sim and display system in a more permanent configuration and setup.

Preassembled the mirror frame; the platform to hold the frame must be square and level. can't emphasize that point enough. On the initial go around the back legs were a tad short resulting in a very slight tilt to the rear. This combined with the weight of the upper collar produced about a 4-5 inch gap at the ribs joining the ear extensions due to a moment or torque which tried to pull the sections apart. That problem will be corrected with adjustable table levelers inserted in the platform legs when final assembly begins.

Here a few pics before I start taking it apart. It is huge! The new workshop will be 22x17x11.5 feet. With the size and linear length of all the edges and joints forming the chamber, taking extra care and time to form good seals to minimize leakage when drawing down the mylar. As well as corners and joints to form edges to hold caulking and sealants.

Just flat ran out of room in the present space to build and pre-assemble the projection screen, so that will have to wait until later.

Have a great summer and see you all in September

Cheers

[fsaviator]

Looking good, John. I'll be waiting! Have a great summer. Has it stopped snowing there yet?

[tmcnam]

Hi Gene,
I know this was originally the thread for the 2 place general aviation size screen. It sounded like you had completed the design phase and I was wondering if it was at a point you could sell the CAD drawings? I realize the manual may not be completed but thought you might sell the drawings and write the manual as some are built. If so, let me know as I am ready to purchase either drawings or a short kit (although I have a good size CNC router with Aspire/VCarve).

BTW, I built a Rostock Max and lo and behold, who wrote the excellent manual for it...you did! Excellent job!

I apologize if this is the wrong thread to inquire.

Best Regards,
Tim McNamara MD

[geneb]

Tim, due to outstanding patents, I'm not going to be able to publish plans and such like I wanted to.
I'd promised the project to Castle before I fully understood where I stood with regard to the outstanding patent that my design uses. To avoid being turned into a greasy stain on the floor of some courtroom, I decided it would be in my best interests to not provide CAD drawings or plans to anyone else, sorry!

Congrats on your Rostock MAX! I hope you enjoy the machine. It's a blast. :)

g.

[tmcnam]

Hi Gene, I understand completely. Would you be willing to pass on the name of the supplier for the larger mylar?

Thanks,
Tim

[geneb]

Oh certainly! Unfortunately, it's on a sticky note at the office and I'm on vacation this week. Castle, can you post the source I pointed you to for the Mylar for Tim?

I'll send a note to my work address on the off chance he doesn't get to it by Monday.

g.

[castle]

Oh certainly! Unfortunately, it's on a sticky note at the office and I'm on vacation this week. Castle, can you post the source I pointed you to for the Mylar for Tim?

I'll send a note to my work address on the off chance he doesn't get to it by Monday.

g.
Also have been on vacation, but see you have posted the supplier. One comment, depending on the width of mylar you desire they can provide the specified size with one caveat. There is a limit on the size UPS will handle. Above that number you have to ship via freight and that is a tad more expensive. So if you want something for the 737 size, for example, might as well order a bunch (I got a thousand foot roll of 124" width). Never know when you might damage the mylar by dropping a tool, smudging the finish, or whatever. ;-)

[castle]

Also have been on vacation, but see you have posted the supplier. One comment, depending on the width of mylar you desire they can provide the specified size with one caveat. There is a limit on the size UPS will handle. Above that number you have to ship via freight and that is a tad more expensive. So if you want something for the 737 size, for example, might as well order a bunch (I got a thousand foot roll of 124" width). Never know when you might damage the mylar by dropping a tool, smudging the finish, or whatever. ;-)

Ooops, got my numbers mixed up. Bought a 1000 feet of the two side sticky tape and 400 feet of the mylar. That should be enough for 10 "tries" or re-skins of the mirror. Estimating the mirror will require a single section of mylar between 35 and 40 feet in length and about 100 feet of tape. The freight charges are pretty steep, so might as well by a bunch. ;-)

The sim room is progressing nicely. Electrical, heating and drywall should be done this week. Hopefully will have it done is a few weeks and get back to the main event..

Cheers
JW

[castle]

Howdy,
Well after a number of delays due to weather and contractor availability ( the fires and floods the past two years has created a building boom in the area ) the "sim-cave" project is ready for occupancy. started moving in the pieces and such last week in September and began building the mirror frame.

With clear sailing, hope to have the frame done and positioned by the end of November. It is one HEAVY beast! So once it is set in place and sections connected moving it would be just about impossible unless one was to disassemble the sections. Then the plan is to build the projection screen -- another large item, and finally to set the screen and then skin the mylar. The size and weight suggest it's best to have everything in place and set to preclude an accident if the mirror was done prior and while hoisting the screen into place something slipped. With just an open cavity we have more flex and don't have to be as careful when moving around the structure.

[castle]

Howdy,

Time for a progress report and some pics....

8330

Had to back up quite a ways to try and capture the entire frame and with my back against the wall still not enough. so here are shots of the left and right ears..
8331 and the right 8332

My live model was not available to give an idea of size, so the 8' ladder will have to do. ;-) The white ring is the two sided tape. The silver tube on the right edge is the roll of mylar. The team to attach the mylar has been assembled and we're discussing the best way to proceed. For you math/geometry types. consider wrapping a sheet of paper around a cone. In theory, you could calculate the size and shape of the mylar, add a margin , find an open basketball court, and cut away. In practice, think we'll go at it starting from the center and work toward each ear one side at a time.

8337 8338

I made some major mods to the spider design to lighten the weight and allow for assembly "in-place". Reduced the width of the arms and added doublers to retain strength and added a member to the hub to join the rear arms. The lower portion of the projection screen arc was hoisted into position after the hub and the arms were set in place. The ribs for the screen will be attached after the mylar is in place.

Also going to reduce the weight of the screen by cutting holes in the ribs. This will reduce the weight from around 50 lbs to around 35lbs; not a lot, but every ounce helps.
8343

And finally a shot of the carriage frame to hold the 737 cabin. Installed on casters so as to enable one to slide the unit away from the mirror and provide more space for access to the electronics housed behind the MIP and above the overhead, as well as the flight controls and control loading mechanisms.

8336

Still a few nits to work on as well completing the exhaust setup. We'll probably attack attaching the mylar after the Thanksgiving holidays.

Will be glad when this is done and I can get back to writing/updating software for FlightGear, the 737 glass displays, warping code, and reassembling the cabin to make it all come ALIVE.

Cheers
JW

[castle]

Nuts!!

left ear8347 right ear8348 center8344
Somehow I messed up some of the thumbnails and attachments, so here is a core dump of the missing pics

spider from above 8346 from below 8345

My apologies for the screwup
JW


Howdy,

Time for a progress report and some pics....

8330

Had to back up quite a ways to try and capture the entire frame and with my back against the wall still not enough. so here are shots of the left and right ears..
8331 and the right 8332

My live model was not available to give an idea of size, so the 8' ladder will have to do. ;-) The white ring is the two sided tape. The silver tube on the right edge is the roll of mylar. The team to attach the mylar has been assembled and we're discussing the best way to proceed. For you math/geometry types. consider wrapping a sheet of paper around a cone. In theory, you could calculate the size and shape of the mylar, add a margin , find an open basketball court, and cut away. In practice, think we'll go at it starting from the center and work toward each ear one side at a time.

8337 8338

I made some major mods to the spider design to lighten the weight and allow for assembly "in-place". Reduced the width of the arms and added doublers to retain strength and added a member to the hub to join the rear arms. The lower portion of the projection screen arc was hoisted into position after the hub and the arms were set in place. The ribs for the screen will be attached after the mylar is in place.

Also going to reduce the weight of the screen by cutting holes in the ribs. This will reduce the weight from around 50 lbs to around 35lbs; not a lot, but every ounce helps.
8343

And finally a shot of the carriage frame to hold the 737 cabin. Installed on casters so as to enable one to slide the unit away from the mirror and provide more space for access to the electronics housed behind the MIP and above the overhead, as well as the flight controls and control loading mechanisms.

8336

Still a few nits to work on as well completing the exhaust setup. We'll probably attack attaching the mylar after the Thanksgiving holidays.

Will be glad when this is done and I can get back to writing/updating software for FlightGear, the 737 glass displays, warping code, and reassembling the cabin to make it all come ALIVE.

Cheers
JW

[castle]

We are approaching the moment of truth. Still one major hurdle which is attaching the mylar sheet to the mirror collar and then drawing down the vacuum.

This project is NOT for the faint-of-heart; lots of things can go wrong, anyone of which can doom the project. If the mirror fails to form properly, going to windup with a lot of fire wood.

Here is a pic of the frame with sound deading padding placed between the ribs. Gene and Wayne indicated a problem with vacuum noise echoing as the mylar makes an excellent speaker cone.

And finally pics of the mylar sheet loosely attached with blue tape. Going to take a break for the Thanksgiving holiday and start pasting the mylar to the collar frame this weekend.

Cheers
JW

[wledzian]

Man, the scale of that thing is just boggling. Looking really good - waiting patiently to see that first drawdown video.

[castle]

Man, the scale of that thing is just boggling. Looking really good - waiting patiently to see that first drawdown video.

Here are two pics with the mylar attached and trimmed, ready for the outer clamping collar. this puppy is just TOO BIG to get in a single shot without a wide angle lense. Will draw down the mirror some time next week.

[super2277]

Hows is it going? tested the display?

[castle]

Hows is it going? tested the display?

That is still a few weeks, possibly a month away. In fact, not totally happy with this first try at the mylar and depending on the results next week, might do a reskin. Then once we're satisfied with the mirror and the controller is fully operational, the projection screen will be installed. have already build and tested the warping software, so just a matter of tweaking the parameters, installing the projectors, and firing up the flight simulation. ;-)

JW

[super2277]

Nice! How far away is the screen from the nose? or the window of the cockpit

[castle]

Nice! How far away is the screen from the nose? or the window of the cockpit

The screen is located above the cockpit. I don't have the exact numbers for distances to the mirror, but is quite close at the truncated nose and flares out as you approach the rear of the cockpit. Just enough room to walk between the exterior cabin shell and the lower circumference of the mirror.

JW

[super2277]

Soo this is like the real display like in the professional simulators? do it give you a 45 degrea vertical view too?

[wledzian]

It's designed for a 40 degree vertical view.

[castle]

Here is a URL to a short video of the mirror frame and overhead support for the projection screen with the 2-sided tape (white band) and ready for attaching the mylar. As Wayne mentioned, the size is big. Overall height is close to 10 feet.

The platform is for the 737 cabin and sits on caster for mobility to facilitate access and maintenance.

http://youtu.be/PC-k07i2FAk


Enjoy

JW

[fsaviator]

Looking great, John. I'll tell you, I can't wait to get back to the Springs and come over to fly that beast! You know I'll be looking to build the next one if this works out.

Warren

[castle]

Looking great, John. I'll tell you, I can't wait to get back to the Springs and come over to fly that beast! You know I'll be looking to build the next one if this works out.

Warren

"if this works out" WHAT? No faith. With such great guys like Gene and Wayne providing support, advice, and encouragement how can I fail. ;-)

Check out the YouTube video at

http://youtu.be/UxbusKPiYkc

Impossible to get all the mirror in a single view. The room is only 22x17x11 feet and can't get back far enough and shooting through the window won't work either; besides it is 4 degrees F and snowing outside. ;-)

The mirror is not perfect, a few goofs attaching the mylar, but good enough for a leak check and tuning of the pump controller as well as throwing up an image for adjusting the warping software.

Started on the projection screen this afternoon.

If you have the occasion for a TDY stateside to the Springs, give a call and come over.

JW

[castle]

The projection screen ribs are installed.

[castle]

It has been one long day. Started before the sun came up; out here that is 7:15 and finished after the sun had set. Still need to add a top coat of EkoBond ( the green areas ) to permanently seal the fabric to the frame. And then apply a hot iron at 275-300F to shrink the Ceconite and draw it tight.

Then we'll apply two or three layers of spackling and then sand. And finally a layer of projection screen paint or may be just plain white. You might notice the mylar has been removed. Going to spend some time with the warping software and setting up the projectors. Once that's done we'll reskin and reassenble the 737 cabin; hopefully by the end of January we can start flying.

Cheers
JW

[fsaviator]

Hope you had a great Christmas, Jack! The project is looking great! I am trying to get back there for a couple of days in February. I'll try to peel some time away to swing by.

[castle]

Hope you had a great Christmas, Jack! The project is looking great! I am trying to get back there for a couple of days in February. I'll try to peel some time away to swing by.

That would be great, Warren. If you decide to build one, you will appreciate the size and space required to house it. The woodshop over on 31st street off of 24 have saved the CNC program so that would save a few dollars on setup costs. They did a fine job and the price was very reasonable. Learned a few things along the way and will be happy to share them with you.

JW

[castle]

Time for a project update.

First, January was a lousy month. Came down with a nasty cold that lasted over two weeks and nothing got down. And second, had a bunch of "honey-do's" that needed attention and that left the last few days until the end of the month. Trying to catch up...

The projection screen is not done, the bad news but as the pics show it is just a few more days. The Ceconite fabric is a wonderful piece of technology, around 7 to 11 dollars per yard, work with a water based glue, and is heat shrinkable.

Here are a few pics --- a finished center section with a primer coat of paint, a right side with Ceconite ready for painting, and a left side waiting for fitting, gluing, and heat shrinking of the fabric. Maybe by the end of this month, we'll have a draw down with a full wrap around visual image on display.

Cheers
JW

[JTRACKER]

That's an amazing piece of work! I can hardly wait for the follow-up.

[fsaviator]

I'm in the Springs and looking forward to seeing this. It will be a few years before I am able to build mine but I can see the effort involved

[castle]

Here are a few more pics.

ATM working with equipment I have on hand --- three different projectors and nVidia graphics boards and edge blending is turned off. Not going to spend a lot of time and effort tuning and tweaking and aligning, although might spend a little time refining the warping software to make it more flexible and user friendly. At sometime in the near future, budget permitting, hope to upgrade to HD home theater projectors and high end graphics.

For the math geeks here is a pic of the warp mesh generated by the software. All you have to do is define a point for the projector position, a plane specifying the image size, location, and orientation, and a surface for the projection screen. Then draw a ray (line) from the projector to the image plane and calculate where intersects the screen surface. Go to Paul Bourke's website for the nitty-gritty details,

Need to get on with the task of reskinning the mylar and setting the PID value for the mirror controller. These will be different than the values Gene and Wayne used for their smaller mirror.

Cheers
JW

[fsaviator]

So, back in Germany now. I've got a few minutes to post

While in Colorado I was able to visit Jack and his collimated display build for a dual seat 737 ...all I can say is pics and video don't do it justice. This thing is fourteen plus feet across and after mounting the hanging projector screen, it is almost eleven feet tall. Impressive and truly a study in patience. If anyone has looked into the cost of 1 mil mylar, you'd know why.


Warren

[castle]

The next time Warren visits, we should be up and flying.

The total mirror is actually 17 feet in outside diameter. the mirror radius is 8 feet and the frame or collar to hold the mylar and back panes to form the chamber is 6 inches in width. Add the projection screen and supporting frame and it is just over 10 feet in height. You might be able to get by with a 10 foot ceiling if you eliminate the frame and suspend the screen with cables. Not an insignificant engineering task. The sim room is 22x17x11.5 feet. While adequate, a 22x20 floor area would have been nicer, but the add-on was a compromise with the wife's wishes for a deck area above the room. Anyone contemplating a project like this might want to settle for the smaller version Gene designed for a 14 foot mirror.

As to the mylar, it is not totallyl unreasonable in price, the killer is shipping costs. Way too large to meet UPS or FedEx limits due to length, so you have to use freight which requires a large wooden pallet to hold the mylar roll rigid and prevent damage and since you pay by the pound and distance the charges include the pallet weight that exceed the cost of the material which itself can be heavy. So might as well buy enough for a couple of reskins and then some. ;-)

Cheers
JW

[castle]

Decided to do some wok on the cabin shell. Don't need to be moving big and long pieces of material around with the mylar in place. Will do all the detail work later.

Once the frame, overhead canopy, and exterior is done will move the platform back and out of the way. And that will provide a five foot buffer to work with for installing the mylar. Still a few weeks away, maybe by the end of March. The first flight date keeps slipping. Starting to feel like Boeing. ;-)

Cheers
JW

[castle]

Hi,

For anyone in project management you know schedules should never be cast in concrete but we're getting closer. The cabin shell phase in completed for now and ready for roll back. And the forward projection screen arms have been removed. When it comes time to install the mylar the rear mounts will be raised to clear the collar and camera and mounts removed providing an unobstructed space to layout and align the sheet and avoid the problem we had with the first effort where the arms got in the way.

Still a few more tasks; first need to measure and establish the mount points for FOV of 50 degrees per projector with a 2.5 degree overlap on either side (reduced from initial setup of 55) , then redo the warp mesh. Decided to spend a little more time here with the existing BenQ ST projectors and rewrite the software and make it more interactive and flexible; something that was planned with the new HD units. Besides Gene and Wayne suggested that the glue works best at warmer temps and spring is almost here and while I heat the shop while working it cools overnight. Takes a few days to get a good cure.

Also spent some time with house-cleaning, but want to do one more detailed pass. Amazing the amount of dust and debris one can generate and where it can hide!

Well, that's it for now. Patience is the watch word. ;-)

Cheers
JW

[castle]

Finally ready to reskin the mylar.

here are two pics with and without blending. The ST BenQs are okay for now, but just don't have the FOV and pixel count for a decent overlap region for this setup. Main goal was to come up with a good algorithm to handle the luminence of individual pixels. Using shaders and GPUs to run the blending. Note how well the white clouds are handled.


The line down the screen is a piece of string to help reference the center line of the screen

JW

[geneb]

Jack, is that blending done in code or did you have to "stitch" it manually like what is done in NThusim+ and Sol7?

Looks great!

g.

[xplanematt]

Fantastic work!!! This is a huge project, and it looks like you are carrying on just fine with it! Question: about how wide is your reflective overhead assembly, and how wide is the actual Mylar mirror frame? I am planning a similar setup, and I'm starting with a 10ft diameter back-projection screen from a commercial level-D sim (yep, that saves me all kinds of money and work). My cockpit is about 8ft wide (Sabreliner 60). Reason I'm concerned about the width of the Mylar screen I'm going to need is that I am in the planning stages of building a shop for this beast....if I orient the sim the way I want to, it will have to fit in about 20ft of width. If I have to, I can rotate the sim 90* and get close to 30ft, but that will make ingress/egress of the sim potentially more troublesome (it will be on a trailer for easy removal/maintenance, and for taking to shows).

I'm also interested in the software. It looks like you are using your own, which is awesome. Any plans to share the code? :) I am using my own code for all my interfacing and avionics etc, but the "high end" math required for advanced optical stuff (mostly, anything that involves a lot of calculus) is not my strong area.

Matt

[castle]

Jack, is that blending done in code or did you have to "stitch" it manually like what is done in NThusim+ and Sol7?

Looks great!

g.

It's done in the code and it will get better. Using shaders to run on the GPU; NOT the CPUs. Started with some basic algorithms and working on some improvements based on that paper out of UCI I sent you a while back. Basic approach is to determine the position and color of each pixel in the overlap/blending region, apply the algorithm, and adjust the color and luminance in the frame buffer before it is sent down the graphics pipeline.

JW

[castle]

Jack, is that blending done in code or did you have to "stitch" it manually like what is done in NThusim+ and Sol7?

Looks great!

g.

It's done in the code and it will get better. Using shaders to run on the GPU; NOT the CPUs. Started with some basic algorithms and working on some improvements based on that paper out of UCI I sent you a while back. Basic approach is to determine the position and color of each pixel in the overlap/blending region, apply the algorithm, and adjust the color and luminance in the frame buffer before it is sent down the graphics pipeline.

JW

[castle]

The 2nd hanging went a helluva lot better than the first. Removing the forward arms of the frame and suspending the projection frame provided clear access to the mirror and allowed for easier draping and positioning of the mylar. Couple of spots that might not meet Level D certification, but good enough for now.

Temptation is to attach the vacuum and suck down the mlylar, at least a little bit. But listening to the sage advice from Gene to first attach the clamping mask before the draw down. So that is a still a few days away.

Stay tuned
JW

[castle]

IT WORKS!!

Go to http://youtu.be/LrvjA6dF0PY for a short video.

Was hoping to do a flying demo. Unfortunatly, was way too successful in sealing the chamber and the mylar draws down to the collimated position and beyond with the vacuum pump running at the minimum speed and the controller and pump have to be turned off after a few minutes to avoid over stretching and damaging the mylar. Also need to install and position the two side projectors. The yellow vertical and horizontal lines are reference/alignment aids.

Hope you enjoy the video. Now I have to buy some HD 1920x1080 projectors. Cha-ching!!

Cheers
JW

[castle]

Oops,

that link should be

http://youtu.be/LrvjA6dFoPY

JW

[geneb]

YAHOO! EXCELLENT!

See, I told you there was no need for a fancy vacuum system. Now ya gotta find a _small_ shop vac. :D

You should shoot a walk-around video showing just the mirror with no image on it.

Congrats!

g.

[fsaviator]

Very nice work. I'm with Gene... a nice walkaround video!

[wledzian]

That looks Great! How's the depth effect as you reach the proper draw depth?

[castle]

That looks Great! How's the depth effect as you reach the proper draw depth?

Fair question. At this point, hard to say. Was unable to sit in the cockpit as I had to monitor the mylar draw and disconnect the power to prevent overdrawing the mylar. I did not expect that. With the shop vac set at the absolute minimum, was unable to use the active arduino controller. So I tried turning on the vacuum until the mylar touched the reference point, counting to three, killing the power, and then running back to the cockpit. One thing I did notice. Being unable to fly, I set a visual view point high above the runway in a later trial. While it was fleeting, I did have a real sense of being in the air and looking over the nose down at the runway as the mylar started to relax.

Going shopping for a small portable car vac or something similar. I thought of installing a small air valve on a section of the exhaust pipe, but that might produce a whistling or hissing sound; beside using less power is always the better option.

JW

[castle]

Okay, by popular demand here is a short video of the mirror setup

http://youtu.be/aPga2SGyvoQ

Enjoy

JW

[geneb]

That's great! Thanks for posting it!

I had to laugh at the walls - it just goes to show that building a simulator requires a padded room. *laughs*

g.

[xplanematt]

EXCELLENT video, thanks for the walk around! It sounds like your projection screen is about the same size as mine...and if you ended up with a 17ft frame for the Mylar, that means my planned 20' room will just about do the job. Good to know.

Gene: I'm thinking that's not for mental condition, that's for when you build a motion platform and the darn thing throws you off like a bronco. :)

[castle]

[QUOTE=xplanematt;148438]EXCELLENT video, thanks for the walk around! It sounds like your projection screen is about the same size as mine...and if you ended up with a 17ft frame for the Mylar, that means my planned 20' room will just about do the job. Good to know.

Don't recall if I mentioned room size in the video, the room is 22x17. At 20' it's doable, but you mind find it a little tight. You will need to access the top of the frame to either mount projectors or fold mirrors. Best to do that from the back side, especially after you've attached the mylar.

JW

[vyper883]

Oops,

that link should be

http://youtu.be/LrvjA6dFoPY

JW

Blown away......Completely blown away!

[xplanematt]

Well actually, I still have some flexibility on room size...I could probably squeeze a 22ft building into the spot I've picked out. As for the screen, it is actually going in the middle of the building...the way I have my current layout, there is a small shop/work area behind the screen, with a loft area above that, which overlooks the screen/sim area. This should be very helpful for hanging the Mylar.

Matt

[fsaviator]

Impressive. Looks great! The next time you fire it up can you give us a view from the pilots and copilots seat?

Warren

[super2277]

Amazed!
How many feet is the collimated display in diameter? And do you have any update on the sim?

[castle]

Amazed!
How many feet is the collimated display in diameter? And do you have any update on the sim?

The top is 16' 10" to the outside edge of the top frame and tapers inward to less than 15' at the base. The mirror itself is 16' at the equator and 12' 4" at the bottom.

Not much new to report, the system is up and running. Moved the vacuum to a outside enclosure to eliminate the noise. Once the mylar is drawn into position, the pump speed drops to around 60-70dB; moving it outside lowers it to a whisper.

Not much point in producing videos, the collimation and depth of field is totally lost, just another ho-hum simmer video. However, will find some time to post a video from the right seat once I'm satisfied with the edge blending.

Focus is now on the software; refining the app to build the warping mesh and playing with some techniques and algorithms for edge blending that run on the GPUs. With four HD projectors (1920x1080), two Nvidia cards (GT-640s), and an I7 processor, frame rates are averaging around 45-50 fps depending on how many features are active. Not bad.

Cheers
JW

[xplanematt]

Sounds like impressive frame rates for just running on one PC! I'm glad to hear about your screen dimensions....I am building a shop for my Sabreliner, and all I can do on width is about 20ft. My BP screen is about 10ft diameter, same as yours. Question: approximately what is your vertical distance from the pilot's viewpoint to the bottom of the screen? My Sabreliner is going on a trailer (at least, that's the plan so far) and I will be limited in how close it can be to the screen.

[castle]

The cockpit firewall starting at the base of the center column of the windscreen is one foot from the lower collar of the screen. You might want to review the physics of concave mirrors. You need to be inside one focal length in order to form a virtual image. The eye viewpoint is just a tad over 3.5 feet to the mirror, give or take a few inches.

obviously, you'll need to remove the nose section.

JW

[xplanematt]

Hmmm, I may have to re-think this display system. I realize I need to end up no further away than the focal point of the mirror, but the somewhat odd shape of this back-projection screen I have makes me a little unsure of how my mirror is going to look. It's a spherical section, but it looks like the curve changes towards the top (the angle becomes more extreme, or so it seems). Cutting the nose off is a no-go with this project....there is still a ton of intact original wiring, the 750VA instrument inverter and the #1 inverter, and all of the original avionics racks and connectors in the nose. Plus I want it to look good for shows. :)

Anyways, this means the pilot's viewpoint has to be a minimum of about 10ft from the screen. Surely I could just scale up the mirror size to get it out away from my nose. OTOH, the nose *does* slope down, and you say the bottom bow is only 1ft below the bottom of the windscreen....so I might be able to place the screen ABOVE the nose and bring it closer than 10ft.

I'm having trouble visualizing the geometry on your setup. How can your screen have a diameter of around 16ft, yet the pilot's viewpoint is only 3.5ft from the screen? Is it not a circular 180* shape?

Thanks for sharing all this info, it is hugely helpful for my own planning purposes. I am really pushing for a similar system, but I don't know if the building dimensions I have to work with are going to be enough for the size of my cockpit.

Matt

[castle]

Hmmm, I may have to re-think this display system. I realize I need to end up no further away than the focal point of the mirror, but the somewhat odd shape of this back-projection screen I have makes me a little unsure of how my mirror is going to look. It's a spherical section, but it looks like the curve changes towards the top (the angle becomes more extreme, or so it seems). Cutting the nose off is a no-go with this project....there is still a ton of intact original wiring, the 750VA instrument inverter and the #1 inverter, and all of the original avionics racks and connectors in the nose. Plus I want it to look good for shows. :)

Anyways, this means the pilot's viewpoint has to be a minimum of about 10ft from the screen. Surely I could just scale up the mirror size to get it out away from my nose. OTOH, the nose *does* slope down, and you say the bottom bow is only 1ft below the bottom of the windscreen....so I might be able to place the screen ABOVE the nose and bring it closer than 10ft.

I'm having trouble visualizing the geometry on your setup. How can your screen have a diameter of around 16ft, yet the pilot's viewpoint is only 3.5ft from the screen? Is it not a circular 180* shape?

Thanks for sharing all this info, it is hugely helpful for my own planning purposes. I am really pushing for a similar system, but I don't know if the building dimensions I have to work with are going to be enough for the size of my cockpit.

Matt

You can view the setup on some videos posted on youtube. Search on "737castle". If you go back through this thread you can also see some picsas it was being built. The screen is circular, but not a hemisphere

JW

[wledzian]

It's the screen, not the viewer, that needs to be within 1 focal length of the mirror. The optics design for Castle's mirror were based on the pilot separation, with the two pilots and the mirror centerpoint forming the three points of an equilateral triangle.

[GodAtum]

Amazing, when are you planning to sell it?

[geneb]

We're not. At least until after 2017 when a patent that the design relies on expires.

Even then, it may only be a plans-only kind of thing. Anything more wouldn't be able to bridge the hassle/income gap. :)

g.

[GodAtum]

We're not. At least until after 2017 when a patent that the design relies on expires.

Even then, it may only be a plans-only kind of thing. Anything more wouldn't be able to bridge the hassle/income gap. :)

g.

Ah OK :) You mention in your original post about a vendor and a CD being made available. How do i get those?

[geneb]

You don't. Not until after 2017. ;)

Rockwell-Collins would turn me into a greasy smear on the pavement if I start selling that thing before the patent expires.

g.

[xplanematt]

*headslap* Of course, Wayne, I hadn't even realized that the BP screen needs to be in the focal point of the mirror! Thanks for pointing that out. Seems I should still be able to upsize the mirror and just move my existing BP screen, no?

When you speak of the pilots and the mirror center point forming an equilateral triangle, are you saying that the center point of the mirror is the center of the sphere that the mirror is (theoretically) part of? That would mean the corners of a 180* mirror would not be directly to the right and left of the pilots. Am I misunderstanding?

[wledzian]

Matt -
No, you can't simply upsize the mirror and move your existing screen, as the screen size needs to scale with the mirror.

When talking about the centerpoint, I'm actually referring to the vertical axis of symmetry shared by both the mirror and the screen. Ideally, the eyepoint would be along this vertical axis as well, as this would make the optics identical in all directions. Practically, however, this defeats the purpose of a cross-cockpit collimated display, as you can't have both pilots in the same spot at the same time.

Since the mirror is a sphere, there is spherical aberration in the image - the collimation is not perfect. You could move the pilots straight outward from the center, but that would cause the point of maximum distortion to lie essentially directly in front of each pilot, with the points of minimum distortion at +/- 90°. In order to improve the visual, the pilots are moved forward at the same time. Putting them at the corners of an equilateral triangle is not an optical necessity, merely a convenient compromise. As you said, this places the corners of a 180° mirror behind the pilots, but due to the collimating effect, the pilots will still see a nearly correct image when they look left and right, just as they still see a nearly correct image when they look forward, even though they're not directly in line with the center of the mirror.

[xplanematt]

Ah yes, I see now why I can't just upsize the mirror. I keep thinking in terms of front projection (what I'm using now) and not a mirror. As many women say, mirrors are not very forgiving. :)

Thanks for the further explanation on spherical aberration. I have considered that being off-center from the mirror would throw off the image a bit, but I hadn't given a lot of thought on how best to handle it. I was misunderstanding your comment previously, I was thinking of the spherical origin of the mirror, and moving the pilots *backwards* from there (so the mirror would actually be IN FRONT of the pilots). But you're saying the pilots move forward as they move from the centerline of the mirror, which explains why Castle is so close to the mirror's surface.

There is one thing I don't understand: how is this system collimated? As I understand collimation, it simply refers to light rays being redirected so that they are parallel to each other (ergo, the Fresnel lens). What we're doing is simply making a mirrored image that is curved so that we see it in 180* (or so), and putting the reflected image in nearly the same plane as the pilot, so that the image "moves" with the pilot as he moves in the cockpit (that it, we're not looking at a fixed point on the physical mirror in front of us). I recall at Flight Safety once I used the word "collimation" in reference to the screen above the cockpit, and the sim tech was quick to point out that it was not a collimation screen, but simply a back-projection screen. Does bouncing the image off the front-projection screen in your setup cause the light rays to run parallel? That *would* be desirable, I'd think, as it would make the image look further away.

What I need to do now is work out how big my mirror should be for my BP screen size...time to look up those patents from Rockwell, it seems. Now I'm worried that it might come out too small for my cockpit, especially if the pilots have to be inside the mirror. I would think it's going to come out quite large, as the sim it came from was large...I think it even had the complete nose section intact. But, if it's too big, it won't fit into the limited space I have to build my sim shop....arrrghh! I suppose in the worst case I will just build a cylindrical (or spherical, if I get ambitious) "wall" in my shop, and shoot projectors onto it directly. That would still be awesome'ish. :)

[geneb]

The mirror is the part that makes the collimation happen - the shape of the mirror in combination of the shape of the screen is how it works. Wayne can describe it better, but that's the gist of it.

See here: http://en.wikipedia.org/wiki/Full_flight_simulator

Read the section titled "Collimated Cross cockpit displays"

g.

[wledzian]

You mention collimation with a fresnel lens, so I'll start with that. With lens-based collimation, the screen is placed at the lens focal length, so that light rays diverge from a given point on the screen, pass through the lens, and continue on parallel to each other on the other side of the lens. As with a lens, a concave mirror has a focal point. More accurately, a concave parabolic mirror has a focal point. A spherical mirror does not have a single focal point, but if you assume a small enough aperture and a large enough mirror radius, the focal region becomes acceptably tight, in this case smaller than a pixel on the screen.

As Gene points out, the collimation happens at the mirror, not the screen. The screen does, however, play a very important role. As seen in the image below, each sightline from the pilot reflects off the mirror and intersects the screen. In order to allow the mirror to produce a collimated image, the screen geometry is chosen so that rays from a given point on the screen are parallel when they reach the pilot. In actuality, the calculation is performed by casting multiple parallel rays from the pilot's eyepoint and slightly above and below the eyepoint, and determining the intersection of these rays after they've reflected off the mirror. If the screen is too close to the mirror, the image will appear too close to the pilot, and if it's too far away, an image won't form properly (this is known as overfocus), and will quickly cause eye fatigue.
9397

Let's take a look at a bundle of rays coming from the screen.
9398

In this case, I've selected the horizon point on the screen. Notice that at the circle representing the pilot's viewpoint, the rays are nearly horizontal (ok, not quite, as I couldn't get the rays to cast from exactly the horizon point). They remain nearly horizontal if the pilot moves his head upwards or downwards. This effect holds true in the horizontal plane as well, so that the pilot will still see a point directly in front of him with both eyes. Because both eyes see the image at the same angle, the image appears far away. It holds true well enough that the pilot can move his head quite a distance, and still see the same point in the image as directly in front of him. For a small display, the acceptable distance may be several inches; for an airliner-sized display, the acceptable viewing volume can be several feet across, accomodating both pilots.

If you take a close look at the above image, you may notice that the rays aren't perfectly parallel; if the pilot is above the design point, the horizon appears very slightly high, and if he's below the design point, the horizon appears slightly low. This is the effect of spherical aberration. As seen in the next image, if you go too far away from the design point, this aberration, in the form of severe displacement (wrong angle) and overfocus (rays diverge), becomes more apparent.
9399

If the screen is too close, the image does not appear at infinity, but rather at some finite distance. In the image below, the light source is moved forward of the screen to produce underfocus. I've moved it a large distance forward to exaggerate the effect, but this effect is present for any point in front of the screen. Notice that the rays reflected from the mirror, if traced back through the mirror, would appear to converge at some nearby distance. In this case, the image would appear very close, defeating the purpose of the collimating mirror.
9396

In reality, the collimating optics system is a compromise. Moving away from the design point, as is mandated by having two pilots which cannot not co-located at the exact vertical axis of the mirror, ensures that there will be spherical aberration, and thus some overfocus. Fortunately, an image doesn't need to be at infinity to appear distant; At a distance beyond 30 to 50 feet, stereopsis (our ability to judge depth due to stereo vision) plays less of a role, and other cues such as perspective, shadow, and contrast begin to play a much stronger role. Fortunately, in these areas, current graphics do pretty well. This allows the optics designer (in this case, me) to place the screen slightly forward, eliminating or at least strongly reducing any overfocus, while still keeping the nearest image well beyond 50 feet.

If you can give me the specs on your existing screen, I can crunch some numbers to see if I can fit a mirror to it. I'll warn you ahead of time, though, if it came off a large sim, it will need a large mirror.

-Wayne

[xplanematt]

Wow, you are a wealth of information, Wayne! I had to read your post several times....it made a lot more sense after I waited a day or two and came back to it. :) I still don't fully understand the optics, but you've made it a lot clearer for me. Now I see why the sim tech was not calling the screen a collimation screen, as it does not do the collimation...the mirror does.

Well, no wonder these big-sim systems look so good...getting the image out near infinity must be HUGELY beneficial for the immersion factor.

I got some numbers on my screen..it's a big ol' thing:

Height: 48"

top bow radius at center: 65.5"
bottom bow radius at center: 60"

top bow diameter: 134"
bottom bow diameter: 124"

Seems it's not a *perfect* circle, but slightly oblong. What other dimensions do you need? I assume you also need to know the radius and vertical location of the screen's deepest point (largest radius), but I'm not sure how exactly to measure that accurately. I ball-parked it best I could with a tape measure:

Vertical location: 20" from top bow
Radius: 67"

Since the "equator" is not at the vertical center of the screen, I'm not really sure how close I am to a perfect spherical section. And I highly doubt I can get the tech data from the manufacturer.....

Another note on this screen: the inside surface is very smooth and shiny, the outside surface has a frosted appearance. I *think* there are at least two layers to this thing. Presumably, light passes through the shiny layer, and is diffused by the frosted layer. I have tested it with a projector from both sides. Putting the projector inside the screen (as it was intended) yields a sharp, gorgeous, very bright image on the outside of the screen, and actually shows up fairly well on the inside surface (but with lots of weird reflections and highlights). Beaming from the front of the screen gives a fairly usable image on the inside surface, but it's a bit fuzzy. Again, there are lots of funky reflections and highlights being thrown off by the shiny inner surface. Seems I recall the outside image was not as clear when beaming onto it from the outside, but I can't recall exactly (been a few months since I had it set up). Perhaps the inside layer actually has some optics to it that help it look sharp when diffused.

Matt

[wledzian]

Sounds like what I'd expect a rear-projection screen to look like. You're correct; the projectors beam through the shiny inside surface and diffuse on the exterior surface. The reflections on the inside are just the reflections of other parts of the screen - the bane of highly curved rear projection screens. Basically, contrast is reduced because in addition to the direct light from the projector, you're getting lots of scattered light from the rest of the screen. If you can make the inside surface highly reflective to off-axis light, you increase the contrast, since less of the scattered light gets through to the viewing surface.

Some quick work with my calculator comes up with a mirror radius of 9.5 feet, which just happens to be a radius that Barco offers.

I'm not entirely surprised that the screen is not perfectly round; I'm sure the pros have some more advanced tools to calculate an acceptable screen shape that produces a better image for both pilots.

[xplanematt]

The more I learn about this screen, the more I like it. :)

When you say 9.5ft, are you talking about the mirror at its deepest point, or do you mean one of the bows? If the latter, that is almost perfect.....my Sabreliner is 12ft long (including radome), the pilot's head is going to be about 1 to 2 feet from the back of the cockpit (depending on where the seat is positioned), and I can get at least another foot of clearance by pulling the radome. And I was planning for a 20ft wide building, but I may be able to squeeze in 24ft or so to allow for the mirror support structure. I assume the shape of the mirror should match the projection screen's profile exactly?

Alright, I'm off to the backyard to get new measurements for the shop!

[wledzian]

9.5 feet is the radius of the sphere that defines the mirror. The lower bow will be closer in, at about 84 inches radius.

[xplanematt]

Awesome, I think I can work that. I'm guessing the Sabreliner 60 nose is close to the same size as the Lear 60 nose, hence the choice of a 9.5ft screen (just the right size to go in front of the cockpit).

This changes my shop layout a bit. I will be doing a 24x25ft floorplan (my city allows a max of 600sqft for outbuildings...), that should provide enough space for the mirror structure, plus the trailer/sim setup.

Wayne, thank you again for all the info, it is invaluable! I am sure I will be back with more questions once the shop is built and I begin the mirror build. :)

Matt

[geneb]

If they have a max for outbuildings, just make it an addition to the house and make it bigger. :D g.

[xplanematt]

That is exactly what my wife suggested! Unfortunately the only side of the house that has room for expansion is also where all the utilities come in....gas, electric, cable, even the AC unit is situated next to that wall, AND the sewage line goes right next to it! I don't really see a way to make it work.

Matt

[geneb]

That sucks. Can you make the outbuilding 2 stories? That way you could have a workshop above... Better yet, you could move. :) g.

[xplanematt]

The poopie-heads thought of that too...10ft walls max, 15ft max roof peak! I tell ya, having been raised in the country, this city living is a rude awakening. And this city is actually pretty loose and non-restrictive compared to many other places, and there is no HOA (I would *never* live under an HOA). Where I come from, if you wanted to build something, you go to the lumberyard, pick up what you need, bring it home and start building the same day.

Moving? Now THAT is taking the hobby to an even further extreme! :P Naww seriously, I like my house too much, and the fact that it's safely below my means...yes I want a quick mortgage payoff. :) Though I do have an idea in the back of my mind to eventually buy some property in the country and build a bigger shop for more sim projects...........

Matt

[geneb]

Can you have two pole-barn style buildings made and use one for a shop and one for a sim room? :) g.

[xplanematt]

Yes, two 300sqft buildings.... :/

I applied for my building permit last week, and discovered that even though I generally only have to be 10ft from the back of the property and 5ft from the side, my property has a "utility easement" that requires 10ft from the side! I am now down to a 21x26ft building and sacrificing a fair portion of my second, full-length driveway (where the Sabreliner currently resides). HOPEFULLY they will at least approve THAT.

To keep this somewhat O/T....this weekend at CockpitFest I discovered the importance of isolating my visual system from stray light. My old sim has, until now, only been used indoors. We had everything in a hangar at the Cold War Air Muesum in Lancaster, with the doors partially open. The daylight mostly washed out my projection screen. My enterprising wife helped me come up with a temporary cover for the sim and screen, which made it usable. I think I will either not put windows in the shop, or use some sort of window-blind assembly that provides a complete light seal. Any ideas?

Matt

[jthiani]

Awesome project. Im in awe !!! I will be embarking on a similar project and any help is much appreciated. Castle, i tried to pm you about coming to see your setup., not sure if it sent though

[castle]

It has been a long, long time since my last post. Finally got around to reskinning the mirror. Lots of folks, friends and neighbors, wanted to come over and fly and kept putting of the job. Took best part of 3 days; one to tear it down and prep and 2 to position and attach the mylar. Just about perfect ;-) The pics tell the tale..

Will take a moment to pass along some "lessons learned"

Gene: if and when you throw together a kit or set of plans, lose the spider arms, you need to provide a scheme to position and suspend the screen for two reasons; first for the 16' system you need a minimum of 4 projectors and the arms get in the way, and second, you need to position and drape the mylar sheet over the top prior to taping. After I had the projection screen attached, calculated the CG of the structure, defined the suspensions points, and once that was done removed the arms. The rigging allows for adjusting, as needed.

Reduce the weight of the screen by reducing rib weight and use ceconite fabric and a thin slurry to cover the material once it is attached and heat treated. That will also allow for a lighter frame.

As you work your way around the frame attaching the mylar you can use blue painters tape attached to the front side of the mylar to hold the mylar away from the glue as you remove the covering from the tape. Work from bottom to top in 3 inch sections ( the width of tape ). Do not stretch the material, just keep it taut. At the ends position the tape sections vertically.

Still need to attach the clamping pieces.

Cheers
John

[wledzian]

Castle, that looks spectacular. Glad to hear that this skinning went so well. Did you draw a line around the edge on the last one to monitor slippage? I know mine looked beautifully pleated like that until the first drawdown, but has always had just a little bit of stretch ever since. The marker line hasn't budged, so I know it hasn't slipped. Yours has seen much more usage than mine, however. I've finally got mine running again, and am hoping that slippage doesn't become an issue.

Jthiani, looking forward to demoing for you this weekend.

[castle]

[QUOTE=wledzian;158180]Castle, that looks spectacular. Glad to hear that this skinning went so well. Did you draw a line around the edge on the last one to monitor slippage? I know mine looked beautifully pleated like that until the first drawdown, but has always had just a little bit of stretch ever since. The marker line hasn't budged, so I know it hasn't slipped. Yours has seen much more usage than mine, however. I've finally got mine running again, and am hoping that slippage doesn't become an issue.

Yes, I drew a line and that was the main reason for the reskin. Just a small section at the rear of the top left edge had slipped and when drawn the mylar was contacting the rib. The rest of the mirror was holding fine. Turns out that was a portion that was exposed to direct sunlight through a shop window at sunrise over a two week period a while back. Tried to do a repair with two "ugly" schemes, first used a heat gun to shrink the mylar in that area and that helped and since it was on the far left rear quadrant did not impact the rest of the visuals but the glue was still losing after a couple of weeks so stuck a large piece of mylar (about a foot square) over the area but that also proved futile in the long run.

On this job, also used a paint roller to apply pressure to the tape prior to attaching the mylar and repeated the action after the mylar was attached. Will be doing the same with the clamping layer. Thinking of using two applications of the tape, one section onto the mylar, roll press it to the mylar, than a second layer onto the clamping sections. Roll press those parts, and then remove the cover sheet on both, attach to the frame, roll press again, and finally apply the screws to the clamping mask. And blocked the sunrise illumination with curtains and blinds.

One thing you might notice in the pics, the mylar attached to the collar is very smooth maximizing the surface contact between the mylar, glue, and collar. This is a result of the procedure to first fully drape the mylar over the entire and using the blue tape to hold the mylar away from the glue as the cover sheet is removed from the glue, section by section.

This is 1 mil mylar. If I do this again might consider using 1/2 mil stuff, although I have enough 1 mil for about 2 or 3 more reskins.

John

PS, say hello to Joe for me. :-)

[geneb]

Agreed on the support arms. It was my first ginormous mirror cell design. What can I say? :D

An ink brayer would work as a good replacement for a paint roller I think.

g.

[jthiani]

looks great John ..... i must make another trip there and stay a bit longer. Tomorrow i leave for seattle and i really look forward to meeting Wayne and Gene and seeing there setup. Im also just about ready to embark on my build. Been working on the motion base thus far and just about done with it

[fsaviator]

I happen to be in Colorado Springs for a few days and so I swung by to see "Castle" and the progress on the collimated display. All I can say is... Wow. Bottom line, I didn't take pictures as they do not do it justice (really I was too stunned to remember).


I've seen pretty much every type of display possible in our little sim world and I will say that without a doubt, short of buying a Level D sim, you will not beat this collimated display.

I'm still speechless. I felt as I could reach through the windows and touch the clouds. I was able to take off, fly a circuit and land on the runway, visual, without crabbing, with the same view from both seats.


Just had to share.

[jthiani]

I happen to be in Colorado Springs for a few days and so I swung by to see "Castle" and the progress on the collimated display. All I can say is... Wow. Bottom line, I didn't take pictures as they do not do it justice (really I was too stunned to remember).


I've seen pretty much every type of display possible in our little sim world and I will say that without a doubt, short of buying a Level D sim, you will not beat this collimated display.

I'm still speechless. I felt as I could reach through the windows and touch the clouds. I was able to take off, fly a circuit and land on the runway, visual, without crabbing, with the same view from both seats.


Just had to share.

I must completely agree here .... i had the very same reaction when i saw this display last year. It is nothing short of the real thing !!!!!

[castle]

Hi,

Away from the project for several months; other pressing matters and priorities. Finishing up some software I started last year. Have been using Immersive Pro for creating the warp mesh. A nice program and reasonably priced, but a little limited for working with compound curved projection screens. One aspect I did not like was having to move individual control points to adjust for the unique radius of the screen at each control point. It was a PITA and tough to get uniform gradations from point to point as the radius changed.

Since the geometry the screen and mirror are uniform and can be expressed mathematically, it was just a question of developing an algorithm to crunch the numbers. The program produces a nice mesh that can be adjusted by varying the input parameters in real time that describe the geometry of the system. You do NOT move control points manually. The resultant control points are saved in an .xml file that can be imported into Immersive Pro for final "tweaking" and edge blending.

Would be interested in user feedback as to whether or not such a program is useful, so if anyone would care to play with it, send me a request via PM and I'll send you the file along with instructions and commands for use.

On another note, might be moving the sim to Denver this summer. More later as the plans firm up.

Cheers
John

[jthiani]

Nice to see you back here John ..... was wondering where you disappeared to lol ... I am about to start my display build and would be interested in trying this out. Im still working on the motion base and getting it finalized

[castle]

Nice to see you back here John ..... was wondering where you disappeared to lol ... I am about to start my display build and would be interested in trying this out. Im still working on the motion base and getting it finalized

Hi Joe,

My email server was off-line and when I reinstated the service most everything was erased. Unable to find your personal email address. Send me a short FYI and I'll send you a copy.

Jack

[fsaviator]

Great to see you back at it, Jack!

[wledzian]

Jack - glad to see you're still at it. I don't use Immersive, but I'd love to take a look at it.

[JTRACKER]

Castle, do you have a design available? Yours looks different than Genes. I don't recall the ribs.

[castle]

Castle, do you have a design available? Yours looks different than Genes. I don't recall the ribs.

Not sure what pictures you might be referencing or comparing. The design is pretty much what Gene and Wayne provided way back when,

I did modify the back panels to fit between the ribs and used ceconite fabric to cover the projection screen; other than that it is the design as provided by Gene.

O! and also removed the supporting arms for the projection screen and suspended the screen from the ceiling. Made attaching the mylar a helluva a lot easier.

You might check with Gene if he has updated the design from over two years ago.

Jack

[castle]

Hi,

For those of you who got a copy of the warping software there is a small bug. The y axis keystoning value is not saved. The value loaded in at the start is saved. I'll try to get a fix out to you all this week. In the interim, you can hand edit the .conf file.

If you adjust y keystone value, save the files as before, and note the y-keystone value. Then edit the .conf file and enter this value for the next session, The x axis keystone value is saved.

John

[JTRACKER]

Maybe just my eyes. I guess I need a bigger screen :-)
Thanks

[JTRACKER]

Hi,

For those of you who got a copy of the warping software there is a small bug. The y axis keystoning value is not saved. The value loaded in at the start is saved. I'll try to get a fix out to you all this week. In the interim, you can hand edit the .conf file.

If you adjust y keystone value, save the files as before, and note the y-keystone value. Then edit the .conf file and enter this value for the next session, The x axis keystone value is saved.

John

Castle,

I've been away far too long I think and have another question for you. What warping software are you referring to? I haven't committed to any version yet and am curious.

[castle]

Castle,

I've been away far too long I think and have another question for you. What warping software are you referring to? I haven't committed to any version yet and am curious.

Rewrote a small app to build a warp file for the Immersive Pro display from fly-elise. It was originally written under Linux for the FlightGear program. When I decided to move over to P3D I was unable to port over the open source code from FG to warp the projector screens and had to purchase a 3rd party package such as Immersive Pro to calculate the control points.

So I redid the Linux package to run under Windows. Now the program will run under Linux or Windows and generate mesh control points for either FG or P3D displays. Of course, for P3D you'll have to pony up a few dollars for the warping app, with FG it is "baked in"

John

[castle]

Hi,

we will be moving later this year or early in 2018 to a warmer climate and wondering what to do with the collimated display. It is a beast and, unlike Wayne's smaller system, impossible to move as one piece. But it will break down nicely into 5 sections that will fit into a UHaul or small truck.

Want to build a new redesigned system once we settle into our new home, so it makes no sense for me to haul this cross-country.

This post is a query to gauge any interest from fellow simmers. One thought would be to auction off the system ( to include the vacuum controller, BenQ HD projectors, extra 200' of mylar, or whatever ) via this forum and donate 10 percent of the proceeds to support this website. Otherwise, we'll have plenty of firewood to get us through the winter. ;-)

Any interest or questions; please post via this thread and I'll provide additional info and details as requested.

Cheers
John

[Tom_G_2010]

A few questions:
1. What would be the minimum room dimensions (WxDxH) needed to house the Display system?
2. What is the width on the roll of mylar? Would you consider selling it separately?
3. What is the specific model of the projectors? Similarly, would you consider selling it separately?

[castle]

A few questions:
1. What would be the minimum room dimensions (WxDxH) needed to house the Display system?
2. What is the width on the roll of mylar? Would you consider selling it separately?
3. What is the specific model of the projectors? Similarly, would you consider selling it separately?

The mirror footprint is based on a topside radius of 8.5 feet and a depth of 13 feet. I added on to my workshop with a dedicated "sim room" measuring 22x18x12 feet. You can get by with a ceiling height of 9 feet, but heigher is a plus That is based on a cockpit floor height of 12" above ground level. I was allowing for raising the entire system to make room for a modest motion based platform.

The mylar is one mil material with a width of 116". The largest cost is the freight charge. It exceeds the limits for FedEx or UPS and you need to enclose it in a wooden crate which increases the weight and resultant freight charges, otherwise if you could arrange for an FOB pickup that would make it a lot simpler and cheaper.

The projectors are BenQ W1070/ST with a native resolution of 1920x1080. There are four of them.

There are some videos on youtube under 737castle as well as numerous pics embedded in these forum msgs going way back to the start.

Cheers
John

[xplanematt]

Hi John,

It just so happens that I'm beginning a reorganization of my sim facility (garage....) so that I can move forward with the Sabreliner project. I have a visual system in mind, but something like what you have might be a better option, if it will fit in my garage. I'd considered a GeneScreen (tm), but don't really have the tools or resources to make a sufficiently precise (and large) structure.

How much space does this rig require once assembled? Also, would it fit on a 16' flatbed trailer?

Of course, I'm also keen to know what you might be asking for it.

Matt

[castle]

Hi John,

It just so happens that I'm beginning a reorganization of my sim facility (garage....) so that I can move forward with the Sabreliner project. I have a visual system in mind, but something like what you have might be a better option, if it will fit in my garage. I'd considered a GeneScreen (tm), but don't really have the tools or resources to make a sufficiently precise (and large) structure.


How much space does this rig require once assembled? Also, would it fit on a 16' flatbed trailer?

Of course, I'm also keen to know what you might be asking for it.

Matt

Hi Matt,

IIRC you are located in Moore, OK. Just a stone's throw from the Springs.

As to size, best to allocate a floor space space of 19x12 feet. This provides you walk-around space of 2 feet at the base and about a foot and a half at the top. As to height, you could get by with a nine foot ceiling to hang the screen. This places the base of the mirror frame at two feet above the ground floor and the 737 cabin floor at one foot above the floor.
Depending on how much height you need below the cabin floor for control linkage and such you could go lower.

I assembled the mirror to provide for mobility. It consists of five sections, each with a vertical height of six feet; two ears and three sixty degree sections to form the semi-circular. Each section is bolted together. Once it is disassembled, should all fit into a 5x8 foot UHaul.

Have several hundred hours in the T-39 ( the mil version of the Sabreliner ), this would be a nice fit for your project. The cabin is smaller than the 737, but both seats are closer to the centerline and a larger "sweet spot" for collimation.

Hope this helps. There are some videos on youtube under the handle "737castle" that you might find informative.

Haven't given much thought as how best to sell the system, associated projectors, controllers, etc. Guess a lot depends on the interest this query generates.

I haven't set a price or the best way to sell it just yet.

Stay tuned
John

[castle]

Greetings,

The 737 sim (cabin and collimated display) is up for sale. If anyone is interested, contact me via PM and I'll provide more details and answer any questions,

Cheers
John

[castle]

Hi,Have been considering ending the project for some time now and the time to finally close the project has arrived. Planning to downsize, move to more mild climate, and do more traveling, here and abroad...The collimated mirror is large, 8' radius and includes a 300' x 10' roll of mylar, four BenQ HD projectors, An Arduino controller and optical sensor plus software to control the vacuum, and the screen torus.It can be disassembled into 5 sections that will fit nicely into a small UHaul trailer. As regards the 737 cabin, it is a mix of DIY stuff, an FDS flightdeck and MCDUs, Opencockpit rudder sets and throttle quadrant, overhead panels and pedestal, seats, and flight control yokes and columns, plus the cabin enclosure. Have some spare parts to throw in as well.Asking $5500 for the mirror system, $6000 for the 737 cabin, or best bid above asking. Happy to answer any questions, provide additional pics and info. CheersJohn

[OmniAtlas]

Hi,Have been considering ending the project for some time now and the time to finally close the project has arrived. Planning to downsize, move to more mild climate, and do more traveling, here and abroad...The collimated mirror is large, 8' radius and includes a 300' x 10' roll of mylar, four BenQ HD projectors, An Arduino controller and optical sensor plus software to control the vacuum, and the screen torus.It can be disassembled into 5 sections that will fit nicely into a small UHaul trailer. As regards the 737 cabin, it is a mix of DIY stuff, an FDS flightdeck and MCDUs, Opencockpit rudder sets and throttle quadrant, overhead panels and pedestal, seats, and flight control yokes and columns, plus the cabin enclosure. Have some spare parts to throw in as well.Asking $5500 for the mirror system, $6000 for the 737 cabin, or best bid above asking. Happy to answer any questions, provide additional pics and info. CheersJohnHi John, I've sent a PM, cheers.

[castle]

Hi Ben,sent you a replay via PM. Hope you receive itJohn